article: Mike is seven and begins to go to school this week . It's Sunday . His mother Mrs. Smith doesn't go to work. Mike wants to go to the zoo. He gets up at six thirty and asks his mother to take him there. After breakfast they go to the bus stop. They want to take a No.3 bus to the  zoo .
  "Look ,Mummy!" the boy is calling out, "A NO.3 bus is coming !"
  "No, dear" Mrs. Smith is saying ,"It isn't No.3 It's No.21."
  "You're wrong, Mummy, "Mike is saying. "My teacher says two and one is three !"
question: Mike thinks  _  ,  so he is calling out .
options: Two and one is three a No.2 bus is coming a No. 3 bus is coming a No.21 bus is coming